1. Field of the Invention
The present invention relates to a cleaning solution for semiconductor substrates.
2. Description of Related Art
Recently, Cu wiring is introduced into semiconductor devices, and for the formation of Cu wiring, a chemical and mechanical polishing process (CMP process) is employed.
This CMP process comprises forming grooves or connecting holes in a previously flattened insulating film of low dielectric constant, such as of carbon-containing SiO2 (SiOC), then forming a Cu film, for example by plating method to fill the grooves or connecting holes, and polishing the surface with a slurry containing special abrasive grains and additives to remove Cu in the portions other than the grooves or connecting holes, thereby flattening the surface and forming the wiring or connecting holes.
On the semiconductor substrate after subjected to the CMP process, there are fine foreign particulate substances such as abrasive grains contained in the polishing slurry or polishing detritus and ionic foreign substances such as metal impurities in large amounts. Therefore, it has been demanded to develop cleaning solutions which can remove simultaneously the particulate foreign substances and ionic foreign substances.
As these cleaning solutions, there have been known, for example, those which contain a nonionic surface active agent having a phenylene group such as polyoxyethylenenonylphenyl ether, a compound forming a complex with a metal such as aminoacetic acid or quinaldic acid, and an alkali component (JP-A-2002-270566).